1. Field of the Invention
This invention relates to brakes and, in particular, to a spring-set, electromagnetically released brake requiring a relatively small amount of current for use in releasing the brake. This invention also relates to an improved coil bobbin for use in the inventive brake or other electromagnetic assembly and, in particular, to a coil bobbin that may be secured against movement within an electromagnetic assembly without bonding.
2. Disclosure of Related Art
A conventional spring-set, electromagnetically released brake includes an armature on which a brake shoe or other engagement element is disposed. A spring biases the armature and the engagement element towards a second engagement element, such as a friction surface. The brake further includes a coil disposed about a magnet pole or other ferromagnetic structure and means for energizing the coil. By energizing the coil, a magnetic circuit is established between the pole and armature in order to draw the armature towards the pole and the brake shoe away from the friction surface, thereby releasing the brake.
Conventional spring-set, electromagnetically released brakes often require relatively large amounts of current in order to overcome the biasing force of the spring and release the brake. As a result, these conventional brakes are relatively inefficient. Further, conventional spring-set, electromagnetically released brakes suffer from an undesirable amount of backlash as the brake is set.
Conventional coil bobbins used for retaining the coil in spring-set, electromagnetically released brakes and other electromagnetic assemblies also have disadvantages. These bobbins are typically secured within the assembly by bonding to prevent movement of the bobbin and the coil. Bonding, however, is a relatively expensive and inefficient process.
There is thus a need for a spring-set, electromagnetically released brake and a coil bobbin that will minimize or eliminate one or more of the above-mentioned deficiencies.